When Doomcenter had that 'Episode 1' week they had an interview with the man John Romero; and he mentioned Episode 1 having a space sky. Did this just appear in an early beta or what? Every version of E1 I've seen has a whitish sky.
Does anyone know where the landscape was scanned from? I reckon it looks like the Andes but I've also heard rumours that it could be China...

Seraph as far as location you are correct...those foliage mountains are in and around south east asia (tropics) what many have suggested the landscape is in E1 is all terraformed however about the sky i have no clue...

Actually those mountains(game-wise)are the walls of the crater that the Phobos Base is in.
Taking them from Reality(tm), I say they're from a tropical place, with the greenness all over the mountains' surfaces.

A picture of the real location used for the Ep1 sky featured as a Doomworld pic of the day a few months ago. It was indeed very green by comparison with the on found in DOOM.WAD

As far as the other sky goes, There was another sky in the alpha/bta versions of doom. Got MBF? That should come with a file called BETALVL.WAD. In there is a graphic called SKY1. That could be the graphic you are on about.

I've had a look at that Betalevl file with MBF and I'm not convinced. If that is the space sky that Romero was on about then they didn't just remove the space sky - they changed the landscape as well for the shareware version.
Why? Well it looks cool, but...? It's a mystery for now I guess.